The field of this invention is prosthetic cardiac valves.
Various types of prosthetic cardiac valves have been developed in recent years, most of which are believed to be described in "The Journal of Cardiovascular Surgery," Volume 63, No. 1, January, 1972, pages 131-142 and in "Journal of the Association for the Advancement of Medical Instrumentation," Volume 5, No. 4, July-August 1971, pages 210-217.